I finally figured it out.
To get OrcaSlicer to change from one extruder to the other, I used the gcode at the filament level.
Thet “advanced” tab in the filament definition is where the gcodes go. So for each filament, I assigned T0 for the left and T1 for the right extruder.
Then I placed a few more lines of gcode under that. It works!
It’s a little cumbersome since you may change filaments. I just have the gcodes in a text file and copy them in.
I hope this helps somebody. If you have a better solution please let me know.